For purposes of the present invention, waste paper means paper collected for recycling that is formed in bulk after coarse sorting that consists of softer paper components and stiffer cardboard components. The paper components are delivered by recycling firms to paper factories that use the paper components for the manufacture of newsprint. Newspapers nowadays are printed on paper that consists to a large extent of recycled paper. This assumes that the used, recycled paper will undergo a de-inking process in which the color components are extracted from the cellulose material. This, however, works only with printed paper, but not with colored paper or cardboard. Therefore, the cardboard components must be separated out of the bulk waste-paper to be recycled.
In practice, it is not possible with justifiable expense to completely extract the cardboard component from a normal mass of waste paper. Therefore, paper factories in which waste paper is used to manufacture newsprint still accept a cardboard content of 2.5%. Therefore, after the coarse sorting process, arriving waste paper undergoes a fine sorting process in which not only colored paper content but also the cardboard content are separated. This fine sorting process is performed manually on moving linear transport devices such as conveyor belts by a large number of workers, and is an activity that must be performed under difficult conditions, and is one whose accuracy decreases as the concentration of the workers decreases in the course of a shift.
From the old German patent document 637 056, a sorting facility for household trash by means of which softer components such as waste paper and fabric may be extracted is known. For this, a transport belt equipped with barbs is provided onto which the trash components are thrown, and on whose barbs the softer components, including pieces of paper, are transfixed. By means of a drum that engages at the deflection point of the transport belt equipped with barbs, using hooks into slotted teeth of the idler roller as far as below the support area of the transport belt, the transfixed pieces of paper are stripped off the barbs of the transport belt. Discrimination between pieces of softer paper and relatively stiffer cardboard is not provided here.
U.S. Pat. No. 5,590,789 describes a procedure and a device to sort thermoplastic components from a stream of materials, whereby a barbed roller is used. The thermoplastic components transfixed on the barbs of this roller are stripped off along the circumference of the barbed roller at a distance from the reception point by a suitable device. The device known in the document does not provide a device to extract cardboard from bulk waste paper, nor is it suitable for this purpose.